Methods and Apparatus with Improved Ventilatory Support Cycling

• US 20080283060A1
• Filed: 06/22/2005
• Published: 11/20/2008
• Est. Priority Date: 06/23/2004
• Status: Active Grant

• Current Assignee: ResMed Pty Ltd. (ResMed Incorporated)
• Original Assignee: Resmed Limited (ResMed Incorporated)
• Inventors: Bassin, David John
• Granted Patent: US 8,826,906 B2
• Time in Patent Office: Days
• US Class Current: 128/204.18
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/0069 the speed thereof being controlled by respiratory parameters, e.g. by inhalation
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/06 Respiratory or anaesthetic masks
• CPC Class Codes: A61M 2016/0015 inhalation detectors
• CPC Class Codes: A61M 2016/0018 electrical
• CPC Class Codes: A61M 2016/0021 with a proportional output signal, e.g. from a thermistor
• CPC Class Codes: A61M 2016/0027 pressure meter
• CPC Class Codes: A61M 2016/003 with a flowmeter
• CPC Class Codes: A61M 2016/0036 in the breathing tube and used in both inspiratory and expiratory phase
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2205/3303 Using a biosensor
• CPC Class Codes: A61M 2205/50 with microprocessors or computers

Abstract

A ventilator that delivers air at different pressures to a patient during inspiratory and expiratory cycles of breathing and that cycles from inspiratory to expiratory operation when the patient'"'"'s respiratory flow passes a threshold level. The threshold generally increases from the beginning of inspiration to the end of inspiration. The increase can be linear over all or only a portion of the inspiratory cycle, and the threshold can be adjusted so that cycling is prevented during the initial portion of an inspiratory cycle. The minimum and maximum levels may both be functions of peak flow and the threshold may increase as a function of elapsed inspiratory time. The rate at which the threshold increases from a minimum level to a maximum level may be adjustable for individual patient needs and may be determined from previous breaths.

Claims

1. A ventilator that delivers air at different pressures to a patient during inspiratory and expiratory cycles of breathing and that cycles from inspiratory to expiratory operation when the patient'"'"'s respiratory flow passes a threshold level, characterized by the threshold generally increasing from the beginning of inspiration to the end of inspiration.

2. A ventilator in accordance with claim 1 wherein the threshold increases linearly during at least a portion of the inspiratory cycle.

3. A ventilator in accordance with claim 2 wherein cycling is prevented during the initial portion of an inspiratory cycle.

4. A ventilator in accordance with claim 1 wherein the threshold increases from a minimum level to a maximum level, both of which are functions of peak flow.

5. A ventilator in accordance with claim 1 wherein the threshold increases from a minimum level to a maximum level, each of which is a respective percentage of peak flow.

6. A ventilator in accordance with claim 1 wherein the threshold increases from a minimum level to a maximum level, each of which is a respective predefined amount above a zero level.

7. A ventilator in accordance with claim 1 wherein the threshold increases from a minimum level to a maximum level as a function of elapsed inspiratory time.

8. A ventilator in accordance with claim 1 wherein the threshold increases from a minimum level to a maximum level as a function of both elapsed inspiratory time and an expected maximum inspiratory time.

9. A ventilator in accordance with claim 1 wherein the rate at which the threshold increases from a minimum level to a maximum level is adjustable for individual patient needs.

10. A ventilator in accordance with claim 1 wherein the rate at which the threshold increases from a minimum level to a maximum level is determined from previous breaths.

11. A ventilator in accordance with claim 10 wherein the rate at which the threshold increases from a minimum level to a maximum level is based on the average inspiration time of a predetermined number of previous normal breaths.

12. A method for operating a ventilator that delivers air at different pressures to a patient during inspiratory and expiratory cycles of breathing and that cycles from inspiratory to expiratory operation when the patient'"'"'s respiratory flow passes a threshold level, characterized by the threshold generally increasing from the beginning of inspiration to the end of inspiration.

13. A method in accordance with claim 12 wherein the threshold increases linearly during at least a portion of the inspiratory cycle.

14. A method in accordance with claim 12 wherein cycling is prevented during the initial portion of an inspiratory cycle.

15. A method in accordance with claim 12 wherein the threshold increases from a minimum level to a maximum level, both of which are functions of peak flow.

16. A method in accordance with claim 12 wherein the threshold increases from a minimum level to a maximum level, each of which is a respective percentage of peak flow.

17. A method in accordance with claim 12 wherein the threshold increases from a minimum level to a maximum level, each of which is a respective predefined amount above a zero level.

18. A method in accordance with claim 12 wherein the threshold increases from a minimum level to a maximum level as a function of elapsed inspiratory time.

19. A method in accordance with claim 12 wherein the threshold increases from a minimum level to a maximum level as a function of both elapsed inspiratory time and an expected maximum inspiratory time.

20. A method in accordance with claim 12 wherein the rate at which the threshold increases from a minimum level to a maximum level is adjustable for individual patient needs.

21. A method in accordance with claim 12 wherein the rate at which the threshold increases from a minimum level to a maximum level is determined from previous breaths.

22. A method in accordance with claim 21 wherein the rate at which the threshold increases from a minimum level to a maximum level is based on the average inspiration time of a predetermined number of previous normal breaths.

23. A ventilator that delivers air at different pressures to a patient during inspiratory and expiratory cycles of breathing and that cycles from inspiratory to expiratory operation as a function of the patient'"'"'s respiratory flow, characterized by the ventilator becoming increasingly sensitive to the initiation of cycling as inspiration progresses.

24. A ventilator in accordance with claim 23 wherein the sensitivity increases linearly during at least a portion of the inspiratory cycle.

25. A ventilator in accordance with claim 24 wherein cycling is prevented during the initial portion of an inspiratory cycle.

26. A ventilator in accordance with claim 23 wherein the sensitivity increases as a function of peak flow.

27. A ventilator in accordance with claim 23 wherein the sensitivity increases as a function of elapsed inspiratory time.

28. A ventilator in accordance with claim 23 wherein the sensitivity increases as a function of both elapsed inspiratory time and an expected maximum inspiratory time.

29. A ventilator in accordance with claim 23 wherein the rate at which the sensitivity increases is adjustable for individual patient needs.

30. A ventilator in accordance with claim 23 wherein the rate at which the sensitivity increases is determined from previous breaths.

31. A ventilator in accordance with claim 30 wherein the rate at which the sensitivity increases is based on the average inspiration time of a predetermined number of previous normal breaths.

32. A method for operating a ventilator that delivers air at different pressures to a patient during inspiratory and expiratory cycles of breathing and that cycles from inspiratory to expiratory operation as a function of the patient'"'"'s respiratory flow, characterized by the ventilator becoming increasingly sensitive to the initiation of cycling as inspiration progresses.

33. A method in accordance with claim 32 wherein the sensitivity increases linearly during at least a portion of the inspiratory cycle.

34. A method in accordance with claim 32 wherein cycling is prevented during the initial portion of an inspiratory cycle.

35. A method in accordance with claim 32 wherein the sensitivity increases as a function of peak flow.

36. A method in accordance with claim 32 wherein the sensitivity increases as a function of elapsed inspiratory time.

37. A method in accordance with claim 32 wherein the sensitivity increases as a function of both elapsed inspiratory time and an expected maximum inspiratory time.

38. A method in accordance with claim 32 wherein the rate at which the sensitivity increases is adjustable for individual patient needs.

39. A method in accordance with claim 32 wherein the rate at which the sensitivity increases is determined from previous breaths.

40. A method in accordance with claim 32 wherein the rate at which the sensitivity increases is based on the average inspiration time of a predetermined number of previous normal breaths.